Wire working apparatus



Sept. 10, 1968 E. s. PIERCE WIRE WORKING APPARATUS 5 Sheets-Sheet 1 Filed Jan. 23, 1967 Sept. 10, 1968 E. s. PIERCE WIRE WORKING APPARATUS 5 Sheets-Sheet 2 Filed Jan. 23, 1967 4 0 &\

- Sept. 10, 1968 E. s. PIERCE WIRE WORKING APPARATUS 5 Sheets-Sheet 3 Filed Jan. 23, 1967 P 1968 E. s. PIERCE 3,400,451

WIRE WORKING APPARATUS Filed Jan. 23, 1967 5 Sheets-Sheet 4 Fig. 6

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United States Patent O 3,400,451 WIRE WORKING APPARATUS Edward S. Pierce, 152 Oberlin St., Milbeth Village, Sinking Spring, Pa. 19608 Filed Jan. 23, 1967, Ser. No. 611,062 19 Claims. (Cl. 29-561) ABSTRACT OF THE DISCLOSURE The instant disclosure is of machines for grinding, burnishing and/or straightening either continuous or short lengths of tempered or resilient metal wire or rods.

BACKGROUND OF THE INVENTION The invention relates to the field of grinding, burnishing or shaping continuous or short lengths of tempered or resilient metal wire or rod to remove surface imperfections common to drawn wire and rods such as draw marks, pits and the like and to provide other surface effects as well as to straighten the wire or rod.

Heretofore apparatus has been proposed as illustrated for example by patents to Green 2,497,407, issued Feb. 14, 1950; Stewart 2,293,923, issued Aug. 25, 1942; and Matteson 1,797,174, issued Mar. 17, 1931, to perform one or more of the functions noted above. Such prior mechanisms have not however provided the desired versatility and efiiciency in operation and it is the principal object of the instant invention to overcome such disadvantages of the prior art.

SUMMARY OF THE INVENTION Briefly summarized the invention resides in an apparatus comprising an internal conical annular grinding surface against which the wire or rod is fed. The annular grinding surface may, in one form of the invention, be itself held against rotation but subject to oscillation. In another form of the invention the annular grinding surface may be also rotated either in the same but suitably in the opposite direction from the oscillatory movement. The annular grinding surface may be so formed, as when applied to a wire fed at intervals, to provide special surface effects on the wire as for example successive portions of larger and smaller diameters.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view taken longitudinally through oneform of an apparatus embodying the instant invention;

FIG. 2 is a sectional view similar to the lower part of FIG. 1 but taken at right angles to the showing of FIG. 1;

FIG. 3 is a sectional view taken on the line 3--3 of FIG. 2;

FIG. 4 is an exploded perspective view of certain elements of the apparatus of FIGS. 1 to 3;

FIG. 5 is a view similar to FIG. 1 of a modified form of the apparatus embodying the instant invention;

FIG. 6 is a sectional view taken on the line 6-6 of FIG. 5;

FIG. 7 is a sectional view illustrating a further embodiment of the invention;

FIG. 8 is an end view of the embodiment of FIG. 7;

FIG. 9 is a view partially in elevation and partially in section of a further embodiment of the invention;

FIG. 10 is a perspective view on an enlarged scale illustrating a portion of the embodiment of FIG. 9 and its operation; and

FIG. 11 is a sectional view on an enlarged scale of a wire or rod following its processing by certain embodiments of-the apparatus.

3,400,451 Patented Sept. 10, 1968 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and more particularly to FIGS. 1 to 4 there is shown a mounting 10 comprising spaced rings 11 and 12, respectively, connected by a web 13 which may be rigidly attached to any desired support such as a wall, floor or other suitable member. Ring 12 includes an inner flange 14 forming a stop for the outer race 15 of a suitable hearing such as ball bearing 16. A similar ball bearing 17 has its outer race confined against outward movement by a snap ring 18 fitting in a groove 19 in ring 11. The inner races 20 and 21 of the bearings 16 and 17 respectively are secured in any suitable way to an outer sleeve 22 for rotation therewith. Also secured to the outer sleeve as by stud 26 is a ring 23 defining a pulley 24 for a driving belt such as the V belt 25 illustrated.

The lower end of the outer sleeve, as viewed in FIGS. 1 and 2, supports a circular plate having a rectangular recess 31 (see FIGS. 3 and 4). Recess 31 (see particularly FIG. 4) is defined by a first pair of opposed walls 32 and 33 and a second pair of opposed walls 34 and 35, walls 34 and 35 being spaced apart a greater distance than the first pair of walls. A bottom wall 36 of the recess includes a concentric opening 37 generally ovaloid in shape and having its major diameter perpendicular to and of a length somewhat greater than the spacing of walls 32 and 33 and its minor diameter of a length somewhat lesser than the spacing of walls 34 and 35. Mounted within recess 31 is a unit 40 comprising a rectangular block 41 centrally bored to form a bore 42 extending part way through the block and terminating at a shoulder 44 and a smaller coaxial bore 43 extending the remainder of the thickness of the block. Bore 42 is countersunk as shown at 45. A suitable bearing such as a brass bushing 46 is inserted within bore 42 and a thrust bearing 47 such as a brass was-her or the like is seated on shoulder 48 and surrounds bore 42. A bushing 49 similar to bushing 46 is inserted within bore 43.

Block 41 includes an integral extension 50 of circular cross-section coaxial with bore 42. Extension 50 has a central recess 51 defined by circular lip 52 having an outer frusto-conical wall 53. The diameter of extension 50 at the base thereof is substantially equal to but slightly less than the minor diameter of opening 37. A block 54 of rubber or other readily compressible but resilient material is secured by any suitable means to a lateral sidewall of block 41, blocks 41 and 54 together being so dimensioned as to be readily received within but to fill recess 31, when the resilient block 54 is in its relaxed state.

A'cylindrical tool has an intermediate portion 61 of a diameter to be rotatably received within bushing 46 a forward extension 63 of a diameter to be rotatably received in bushing 49 and a rear portion 64 of enlarged diameter to be received in countersunk portion 45. Portion 64 is provided with a plurality of locking slots 65 for a purpose hereinafter described and forward portion 63 is grooved as at 66 to receive a locking ring 67. The internal surface 68 of tool 60 includes (see FIG. 1) a grinding annulus 70 of generally conical configuration but suitably including, for a purpose hereinafter to be explained, annular grooves 71. The grinding annulus 70 terminates in a cylindrical portion 72 of an enlarged diameter relative to the inner end of the grinding annulus. Grinding annulus 70 is coated with carborundum, diamond grit, carbide or ceramic grits or other suitable abrasive material.

Tool 60 is assembled in unit 40 by inserting the portions 61 and 63 in bushings 46 and 49 respectively and securing it therein by placing snap ring 67 in groove 66. Unit 40 is mounted in plate 30 by compressing block 54 sufiicient- 1y that the projecting portion of extension 50 can pass wall 33 the unit then being inserted in recess 31 until extension 50 reaches opening 37 the compression force on block 54 then being released to allow the unit to assume the position shown in FIGS. 1 and 2. Unit 40 is retained in this position in plate and plate 30 in turn is secured to outer sleeve 22 by segmented plates 73 and 74 which are received in recesses formed in unit and plate 30. Plates 73 and 74 are secured to outer sleeve 22 as by screws 75. As will be observed particularly from FIGS. 2 and 3 when the parts are assembled as described above block 41 and tool supported therein will be off center or eccentric with respect to sleeve 22.

Interfitting within outer sleeve 22 is an inner sleeve the sleeves being connected for conjoint rotation but relative endwise sliding movement by keys 81 confined in slots 82 of the inner sleeve and seated for sliding movement in elongated slots 83 of the outer sleeve. The lower end, as viewed in FIGS. 1 and 2, of the inner sleeve 80 is partially closed by a circular flange 84 defining a funnel shaped opening 85 having a diameter at its mouth slightly less than the diameter of extension 50 at its base. The wall of the funnel shaped opening slopes at substantially the same angle as the angle of slope of wall 53 of extension 50.

The upper end of inner sleeve 80 is closed by a cap plate 86 secured thereto as by screws 87. Cap plate 86 has a central opening in which a bushing or sleeve 88 is secured the bushing being of nylon or other similar material to avoid excessive abrasion of the Wire as it travels therethrough in the manner hereinafter explained. One end of a pressure arm 89 overlies cap plate 86 and is separated therefrom by an annular thrust bearing 90. The end of pressure arm 89 overlying inner sleeve 80 has a central bore of larger diameter but coaxial with the central opening in sleeve 88. Pressure arm 89 is adapted to be moved between the raised position shown in FIG. 1 and a lowered position in which it forces inner sleeve 88, through the interaction of the walls of tunnel shaped wall 85 and the outer wall of extension 50, to shift the rectangular block 41 to position tool 60 concentrically to the sleeve, block 54 of rubber or the like being compressed during such shifting movement. The means for causing the lowering or downward movement of the pressure arm has not been shown but may be any suitable manually or mechanically operated means or electrically operated means such as a solenoid operated device.

In the form of the invention shown in FIGS. 1 to 4 tool 60 is held against rotation with the sleeves by any suitable means. For example such means can comprise a collar having ribs 96 interfitting in slots 65 in tool 60. Collar 95 is held against rotation but permitted to move with the tool as the latter moves in its eccentric path and between its eccentric and concentric positions by a U-shaped spring bracket 97 having one end secured to the collar and its other end secured to a fixed frame member.

Where the mechanism described above is to be employed for the form grinding of a continuous length of wire or the like a wire supply reel (not shown) is supported by any suitable means (not shown) below the device. A manually or mechanically operated gripping device, illustrated only diagrammatically at 98 and which may be of any suitable type, is employed the gripping device being located to guide the wire concentrically of the sleeves and being so constructed or operated as to intermittently release the wire to the grinding tool 60 at the required intervals as to form grind the wire through the intermediary of the grooves 71 of the tool to a desired shape such as that shown for example in FIG. 6. Opposed rolls 100 adapted to be constantly driven by any suitable means (not shown) are supported above the sleeves in position to receive between them a wire passing through bushing 88 the rolls being adapted to exert a slipping drawing action on the wire to maintain tension thereon during the grinding operation and to pull the wire through the device when the gripping action of device 98 is released.

In preparation for the grinding operation pressure arm Cir 89 is moved downwardly to shift the tool into concentric relationship with the sleeve, and the wire is then drawn from the reel, threaded through the gripping device, through tool 60, bushing 88 and between rolls 100. The outer sleeve is then driven through the medium of pulley 25 at a speed of say 8,000 to 15,000 r.p.m. and rolls 100 are driven to exert constant tension on the wire. Pressure arm 89 is then raised whereby the block 41 and the tool 60 carried thereby are shifted into eccentric relationship with respect to the outer sleeve, the tool then exerting a grinding action on the wire held stationary at this point. After a predetermined interval during which the wire is ground to provide a section having adjacent portions of different diameters as determined by the characteristics of the tool, pressure arm 89 is again lowered to bring the tool into concentric relationship to the sleeve and the wire is then advanced, gripping device 98 being opened or released for this purpose, to position a second section of the wire within the grinding tool. Pressure arm 89 is then again raised and the second grinding operation performed. These operations are continued until the desired length of the wire has been ground to produce an effect such as shown in FIG. 11. It will be understood of course the ground areas need not be contiguous as shown in FIG. 11 but can be of any desired spacing and character.

When the device of FIGS. 1 to 4 is to be employed for the centerless grinding or burnishing of a continuous length of wire to a uniform diameter the gripping device 98 is omitted and the wire is drawn directly from the reel preferably through a tension means of any suitable type (not shown) and to the opposed rolls 100. In this case the pressure arm is lowered to shift the tool concentrically to the sleeves only for the initial threading operation the pressure arm then being raised and the wire thereafter being continuously drawn through the tool to obtain a uniform surface grinding or burnishing effect. While the grinding surface shown in FIGS. 1 to 4 may be employed it is preferable in this instance to employ a tool having the grinding surface illustrated in FIG. 7.

The device of FIGS. 1 to 4 may also be employed for the form grinding of the end portions of individual pieces of wire such as the grinding of the points of needles or the like. For this purpose the pieces of wire are successively inserted in a chuck such as that shown at 156 in the form of the invention shown in FIG. 9. Pressure arm 89 is lowered as before to force the inner sleeve downwardly to adjust the tool to its concentric relationship to the sleeves and the chuck is supported by suitable means (not shown) to locate the end of the wire within and in concentric relationship to the grinding surface of the tool. Upon rotation of the sleeves and the raising of pressure arm 89 the end of the wire is ground by what is in effect centerless grinding. The tool may have some special configuration to provide a desired end shape for the needle or other wire element. On the other hand if a pointing or sharpening of the wire is the desired effect a tool having a pain grinding surface such as that of FIG. 7 may be use Referring now to FIGS. 5 and 6 a second embodiment of the invention is illustrated employing for the most part the construction features of the embodiment of FIGS. 1 to 4, such common features being given the same reference characters. Thus in the embodiment of FIGS. 5 and 6 the inner and outer sleeves 22 and 80, respectively, are keyed together for joint rotation but relative endwise sliding movement as in the first embodiment. The tool 60 and the mounting means therefor may be identical to those of the first embodiment except that due to certain features which will be described hereafter, suitably a roller bearing 110, the beaing being of the type which also serves a thrust bearing function, is substituted for the bushings 46, 47 and 49.

The distinguishing feature of the second embodiment lies in the ability of the tool to rotate independently of the sleeve structure and in either direction. The means for this purpose comprises a hollow tube 111 the lower end of which is joined to a tubular washer 112 in any suitable manner. The tubular washer is provided with two diametrically opposed projections 113, although a greater number may be employed if desired, the projections interfitting in slots 114 in the upper end of tool 60. Tube 111 extends through sleeve 80 and beyond the end thereof and beyond pressure arm 89. The projecting outer end carries a collar 115 fixed thereto in any suitable manner the collar including an enlarged portion 116 defining an annular flange supporting the inner race of a ball bearing unit 118. The outer race of the ball bearing unit 118 is supported on an interior annular flange 119 formed in ring 120 preferably integral with an arm 121 which is supported in fixed position from the framework of the machine. Split washers 122 and 123 interfit in grooves in the inner surface of the ring 120 and in collar 115, respectively, to retain the inner and outer races against their respective shoulders. A pulley 124 is affixed to the upper ends of the tube 111 the pulley being adapted to be driven from any suitable source (not shown) by a belt 115. Tube 111 is composed of a material such as a rubberized fabric or the like of the type employed for pressure tubing or hose or may be a hollow wound shafting material or is otherwise of such construction that it has the ability to flex laterally during the travel of the tool in its eccentric path but at the same time transmit torque to the tool.

The embodiment of FIGS. 5 and 6 operates, when employed for either the centerless grinding of continuously moving lengths of wire or for wire shaping, in the same manner as described for the embodiment of FIGS. 1 to 4 except that in this second embodiment the tool is also rotated through the medium of the flexible tube 111 and its driving mechanism. Thus the tool may be rotated in the opposite direction to the rotation of the inner and outer sleeves 22 and 80 to increase the grinding speed over that afforded by the rotation of the sleeves alone. On the other hand the tool may be rotated in the same direction as the sleeves to reduce the grinding speed. A particular advantage of this feature is that the effective r.p.m. may be readily varied to provide the different desired grinding effects while the rate of feed and hence the delivery of the wire remains constant as may be required for subsequent operations thereon. Also very high grinding speeds may be obtained without injury to the device. For example by rotating the sleeve structure at the acceptable rate of 15,000 rpm. previously mentioned while rotating the tool in the opposite direction at up to 15,000 rpm. an effective grinding speed of up to 30,000 rpm. results.

The embodiment of the invention illustrated in FIGS. 7 and 8 is of a simplified construction primarily adapted for operation on -a continuously moving wire for the centerless grinding or burnishing thereof. However it may serve the function of pointing short lengths of wire similarly as the embodiment of FIGS. 1 to 4. In this form of the invention a single sleeve 130 is employed the sleeve being mounted for rotation in the same manner as the outer sleeve of the previously described embodiments. The sleeve has end members 131 and 132 secured thereto as by a series of screws 133 and 134 only one of each series being shown. End member 131 has a central aperture 135 in which a bushing or sleeve 136 of the same type as bushing 88 of the first embodiment is secured. End member 132 has an eccentrically located cylindrical aperture 137 the annular wall of which is defined in part by a flange 138 providing a shoulder supporting the outer race of a roller bearing unit 139. The annular wall of aperture 137 is also defined in part by a recessed wall 140 defining a shoulder for the partial support of the inner race of a roller thrust bearing 141. A hollow grinding or polishing tool 142 which is of generally cylindrical shape includes a flange 143 supporting the inner race of roller bearing 139 and an end portion of reduced diameter defining a shoulder 144 in part supporting the inner race of thrust bearing 141. The bearings are maintained in position and the tool is held against endwise movement relative to end member 132 by a snap ring 145 interfitting a groove in the tool and a snap ring 146 interfitting a groove in the end member. The tool is held against rotation in the bearings by any suitable means but suitably, as illustrated, by the same means as employed in the first embodiment. The hollow interior of tool 142 comprises a frusto-conical mouth 147v terminating approximately midway of the length of the tool, the wall of the mouth portion defining, when coated with a suitable abrasive, an annular grinding or burnishing surface depending upon the particular abrasive employed. The remainder of the hollow interior of the tool comprises a second frusto-conical portion 148 reversed with respect to the mouth and in communication therewith. The outer enlarged end of the mouth portion is of a diameter to extend beyond the centerline C of sleeve 130.

In the embodiment of FIGS. 7 and 8 rolls 149 driven by any suitable means (not shown) are employed to positively feed or push the wire, indicated by dot-and-dash line W, concentrically of the sleeve 130. In operation the wire W supplied from a suitable source or reel (not shown), and after being originally threaded through the tool 142, the hollow interior of sleeve 130 and bushing 136 and to any suitable wire take-up device (not shown), is positively fed or pushed forwardly by the feed rolls 149 into contact with the wall of the conical mouth of tool 142 the wire thereafter taking the path indicated. The wire take-up device may be of any suitable type as previously mentioned but in any event it is of such character that very little if any tension is applied to the wire at the location of the tool.

Referring now to FIGS. 9 and 10 a further simplified form of the invention is illustrated this embodiment being adapted primarily for the pointing and/or straightening of short lengths of wire. The unit which in this instance comprises a cylindrical block 150 is adapted to be mounted for rotation in any suitable way such as in a conventional chuck 151 of a lathe, drill press or the like. Block 150 has an eccentrically positioned conical recess 152 having its apex suitably in communication with a cylindrical channel 153 which in turn is in communication with a conical opening 154 leading from the upper end of the cylindrical block 150, channel 153 and opening 154 serving to permit the movement of air and particles carried thereby through the block. The annular wall of recess 152 is surfaced with a suitable abrasive 155 of any of the types previously mentioned. A short wire length 156 to be pointed is supported in fixed position in a holder or chuck 157 of any suitable type the chuck being located concentrically of the block and in such position that the end of the wire length to be worked contacts the abrasively coated wall of conical recess 152 intermediate its height.

In operation upon rotation of the block ,150 with chuck 151 the end of the wire length is subjected to a grinding action to reduce it to the extent desired as, for example, to a point. At the same time the whipping action to which the wire length is subjected performs a wire straightening function. In this connection, and as will be understood, in each of several embodiments the straightening is inherently achieved by the whipping action to which the wire is subjected.

As will be appreciated from the foregoing description the embodiments of FIGS. 1 to 6 may be employed for either centerless grinding or form grinding of continuous lengths of wire. On the other hand the simplified embodiment of FIGS. 7 and 8 does not permit form grinding but is highly effective for centerless grinding and burnishing. Each of the above mentioned embodiments may, of course, in addition to their other functions be used, as previously pointed out for the embodiment of FIGS. 1 to 4, for pointing short lengths of wire similarly as embodiment of FIGS. 9 and 10. It should be noted that a further function inherently performed particularly by the embodiments of FIGS. 1 to 4 and 7 and 8 is the burnishing of the ground wire as it necessarily contacts the walls of the nylon bushing or sleeve such as bushing 88 of the embodiment of FIGS. 1 to 4 during its passage therethrough. This burnishing effect is enhanced by particles of the abrasive substance which are released during the grinding action and which settle on the bushing.

It will also be understood that in the use of any of the: several embodiments of the invention it is possible to maintain the wire or rod at the desired finished dimensions or character notwithstanding wear or other deterioration of the grinding surfaces by varying the speed of rotation of the tool or of the tool holder or of both, depending upon the embodiment involved, or by varying the rate of feed of the wire and hence the pressure of the wire against the tool. The checking of the wire dimensions may be performed by conventional measuring devices such as diodic inspecting equipment, or an air measurement means. Such devices may, if desired, be employed in connection with suitable mechanisms not herein illustrated to directly modify the factors mentioned above whereby the dimensional characteristics of the wire or rod are automatically maintained. On the other hand continuous manual inspection may be employed and adjustments made manually.

Having thus described the invention in rather complete detail it will be understood that these details need not be strictly adhered to and that various changes and modifications may be made all falling within the scope of the invention as defined by the following claims.

What is claimed is:

1. In an apparatus for working wire, a cylindrical body structure having an axis and including an end structure transverse to said axis with a portion thereof including a conical recess at least normally eccentric to said axis and having an annular wireworking wall, means for rotating said body structure and at least a part of said end structure, and means to advance wire on the line of said axis and into contact with said annular wall.

2. An apparatus as defined in claim 1 wherein said annular wall has an abrasive surface.

3. An apparatus as defined in claim 1 wherein said body structure comprises a sleeve and said part of said end structure is secured to said sleeve, and said portion of said end structure comprises a tool element and there is means mounting said tool element in said part.

4. An apparatus as defined in claim 3 wherein said mounting for said tool element includes means to permit relative rotation between said tool element and said part of said end structure.

5. An apparatus as defined in claim 4 wherein there is means for holding said tool element against rotation with said sleeve.

6. An apparatus as defined in claim 4 wherein there is means for rotating said tool element relatively to said sleeve.

7. An apparatus as defined in claim 3 wherein said part comprises a block containing the mounting for said tool element, said block including resilient means adapted to bias said mounting to an eccentric position with respect to said axis, and there is means to shift said mounting against said bias into concentric relationship to said axis.

8. An apparatus as defined in claim 7 wherein said means to shift said mounting comprises an extension on said block projecting into said sleeve, a second sleeve, means mounting said second sleeve within said first mentioned sleeve for rotation therewith and endwise movement relatively thereto, said second sleeve including means for, upon endwise movement thereof toward said block, cooperation with said extension to shift said block and mounting, and there is means for moving said second sleeve toward and away from said block.

9. An apparatus as defined in claim 8 wherein said extension is of annular configuration and has an inclined surface and said means included in said second sleeve for cooperation with said flange comprises means defining a similarly inclined annular surface.

10. An apparatus as defined in claim 7 wherein said block comprises a rectangular member and said resilient means comprises strip of compressible material secured to said member at one side thereof.

11. An apparatus as defined in claim 7 wherein there is means for holding said tool element against rotation with said sleeve.

12. An apparatus as defined in claim 11 wherein said last named means comprises a fixed support and a resilient U-shaped member having one end secured to said tool and a second end secured to said fixed support.

13. An apparatus as defined in claim 7 wherein there is means for rotating said tool relatively to said sleeve.

14. An apparatus as defined in claim 13 wherein said means for rotating said tool relatively to said sleeve comprises a hollow flexible shaft extending within said sleeve connected at one end to said tool and there is means for rotating said shaft.

15. An apparatus as defined in claim 3 wherein there is a second sleeve within said first sleeve, there is means defining a wire passageway between said conical recess and the interior of said sleeve and wherein said second sleeve includes an end member remote from said recess and there is a bushed opening for the egress of wire from the interior of said second sleeve whereby the wall of said bushed opening performs a burnishing function on wire passing through said opening in contact with said Wall.

16. An apparatus as defined in claim 1 wherein there is means defining a wire passageway between said conical recess and the interior of said sleeve and wherein said sleeve includes an end member remote from said recess and there is a bushed opening in said end member for the egress of wire from the interior of said sleeve whereby the wall of said opening performs a burnishing function on wire passing through said opening in contact with said wall.

17. An apparatus as defined in claim 1 wherein said portion of said end structure includes a tool element fixed in an eccentric position relatively to said axis said tool element containing said conical recess, there is means defining a wire passageway between said conical recess and the interior of said sleeve and wherein said means to advance wire on the line of said axis comprises means for pushing said wire against said annular wall through said passageway and into the interior of said sleeve.

18. An apparatus as defined in claim 1 wherein said cylindrical structure comprises a sleeve, there is means defining a wire passageway between said recess and the interior of said sleeve, and said means to advance wire on the line of said axis comprises means to advance a length of Wire at spaced intervals.

19. In an apparatus as defined in claim 1 wherein said cylindrical body structure and said end structure comprise a single unit.

References Cited UNITED STATES PATENTS 2,498,903 2/1950 Wallace 5173 2,497,407 2/1950 Green 5173 2,293,923 8/1942 Stewart 5l-73 1,797,174 3/1931 Matherson 5173 RICHARD H. EANES, 1a., Primary Examiner. 

